Diabetes, with its associated complications, is one of the leading causes of death and disability in the United States. Among those with diabetes, non-insulin-dependent diabetes mellitus (NIDDM) is the most common type, accounting for over 90% of all diabetic cases. To better understand the disease, a prospective study has been underway for 25 years in a population of Native Americans, the Pima Indians, who have the highest documented rates of NIDDM in the world. The purpose of this current proposal is to investigate the role of physical activity as a potential risk factor for the development of NIDDM in this high risk population. An activity questionnaire had been developed for use in the Pima Indian study to collect reported physical activity data in this population. Utilizing available methods of accuracy testing, this questionnaire was demonstrated to be both feasible and reliable. For this reason, since 1987, this questionnaire has been administered to the Pima Indian participants as part of the data collection scheme at the study clinic. The specific aim of this proposal is to test the hypothesis that physical inactivity in the Pima Indians is associated with a worsening of glucose tolerance, either as an independent risk factor, or through its association with obesity. This will be examined in two separate ways: 1) evaluation of the cross-sectional association between reported physical activity and both blood glucose and insulin levels and the risk factors for glucose intolerance; and 2) prospective evaluation of the relationship between physical activity and the subsequent risk of development of glucose intolerance and obesity in this population. This proposal will provide the necessary supervision and personnel for continued collection of physical activity data in the Pima population to allow for the prospective relationship between physical activity and NIDDM to be examined.